IMPACT OF VOLTAGE ON ELECTROKINETIC REMEDIATED LEAD CONTAMINATED SOIL FOR USE AS ROAD BASE MATERIAL

Abstract

Impact of voltage on electrokinetic remediated lead contaminated soil to determine the soil’s suitability for use as road base material was investigated in this research. Although, electrokinetic remediation method have proven to be more effective than most traditional techniques used in remediating low permeability soils contaminated with lead, there is still the problem of “the optimal voltage of the electrokinetic remediation process†that is most likely to produce the best result. The lead contaminated soil was remediated at 15V, 30V, 45V and 60V. At each voltage applied, index and geotechnical properties tests were conducted on the soils after remediation. Generally, the soil is non-plastic belonging to the A-4 group of soil. There is general improvement in all the geotechnical properties of the remediated soil. These improvements are maximum at 30V, there is little or no further improvement beyond this point. The CBR values indicated that none of the materials is suitable for use as road base material as the results do not satisfy the minimum 80% required. But the materials compacted using BSH met the minimum requirement of 40% CBR value and can be used as sub-base materials. Other results showed that the durability with resistances of 89% and 90% to loss in strength was recorded at 30V and 45V respectively, this, when compared to the resistance to loss in strength of 71% in un-remediated soil has respectively 25.3% and 26.8% durability advantages. It is recommended that 30V is just suitable for remediation purpose since less energy is used during the entire remediation process compared to 45V and 60V. All the UCS values failed to satisfy the 1700kN/m2 and 3000kN/m2 recommended for sub-base and base course materials respectively. With WAS compaction effort, the material remediated at 15V, 30V, 45V and 60V met the requirement of 80% resistance to loss in strength making the soil suitable for use as base course material.

 

KEYWORDS:  Electrokinetic remediation, heavy metal, contamination, California bearing ratio, unconfined compression strength, durability.